1. Field of the Invention
The present invention relates to an energy system, and more particularly, to an energy system capable of protecting a compressor by heating lubricant oil and a refrigerant in a screw compressor.
2. Description of the Related Art
In general, a screw compressor compresses a low-pressure refrigerant gas with a high pressure. The screw compressor cools heat of the refrigerant gas generated between two screw rotors, and lubricant oil is continuously supplied into the screw compressor so that leakage of the refrigerant gas compressed in the two screw rotors can be prevented and a bearing, etc. can be cooled and lubricated. A lubricant oil storage chamber is provided in the screw compressor, and the lubricant oil collected in the lubricant oil storage chamber is supplied to the screw rotors, the bearing, a motor, etc. via each lubricant oil supply line, and the lubricant oil mixed with a refrigerant in the screw rotors is separated and recovered from a lubricant oil separator and then is collected into the lubricant oil storage chamber again.
When a system including the screw compressor stops, a liquid refrigerant is introduced into the screw compressor, and the liquid refrigerant and the lubricant oil are mixed with each other such that the lubricant oil is cooled and the concentration of the mixture is lowered and damage occurs when the screw compressor starts up. Thus, a crank heater, etc. is installed in the screw compressor for warming-up of the screw compressor. However, the crank heater consumes a large amount of power when operating such that the efficiency of the system is lowered. Also, the screw compressor should be managed at a predetermined temperature or less so as to acquire a lubricating capability while the system operates, and an additional device therefor is required.